The fate and impact of Co3O4 nanoparticles in the soil environment: Observing the dose effect of nanoparticles on soybeans.

The widespread presence and distribution of metal-based nanoparticles (NPs) in soil is threatening crop growth and food security. However, little is known about the fate of Co3O4 NPs in the soil-soybean system and their phytotoxicity. The study demonstrated the effects of Co3O4 NPs on soybean growth and yield in soil after 60 days and 140 days, and compared them with the phytotoxic effects of Co2+. The results showed that Co3O4 NPs (10-500 mg/kg) had no significant toxic effect on soybeans. Soil available Co content was significantly increased under 500 mg/kg Co3O4 NPs treatment. Compared with Co2+, Co3O4 NPs mainly accumulated in roots and had limited transport to the shoots, which was related to the particle size, surface charge and chemical stability of Co3O4 NPs. The significant accumulation of Co3O4 NPs in roots further led to a significant decrease in root antioxidant enzyme activity and changes in functional gene expression. Co3O4 NPs reduced soybean yield after 140 days, but interestingly, at specific doses, it increased grain nutrients (Fe content increased by 17.38% at 100 mg/kg, soluble protein and vitamin E increased by 14.34% and 16.81% at 10 mg/kg). Target hazard quotient (THQ) assessment results showed that consuming soybean seeds exposed to Co3O4 NPs (≥100 mg/kg) and Co2+ (≥10 mg/kg) would pose potential health risks. Generally, Co3O4 NPs could exist stably in the environment and had lower environmental risks than Co2+. These results help to better understand the environmental behavior and plant effect mechanisms of Co3O4 NPs in soil-plant systems.

Modulation of starch synthesis in Arabidopsis via phytochrome B-mediated light signal transduction.

Starch is a major storage carbohydrate in plants and is critical in crop yield and quality. Starch synthesis is intricately regulated by internal metabolic processes and external environmental cues; however, the precise molecular mechanisms governing this process remain largely unknown. In this study, we revealed that high red to far-red (high R:FR) light significantly induces the synthesis of leaf starch and the expression of synthesis-related genes, whereas low R:FR light suppress these processes. Arabidopsis phytochrome B (phyB), the primary R and FR photoreceptor, was identified as a critical positive regulator in this process. Downstream of phyB, basic leucine zipper transcription factor ELONGATED HYPOCOTYL5 (HY5) was found to enhance starch synthesis, whereas the basic helix-loop-helix transcription factors PHYTOCHROME INTERACTING FACTORs (PIF3, PIF4, and PIF5) inhibit starch synthesis in Arabidopsis leaves. Notably, HY5 and PIFs directly compete for binding to a shared G-box cis-element in the promoter region of genes encoding starch synthases GBSS, SS3, and SS4, which leads to antagonistic regulation of their expression and, consequently, starch synthesis. Our findings highlight the vital role of phyB in enhancing starch synthesis by stabilizing HY5 and facilitating PIFs degradation under high R:FR light conditions. Conversely, under low R:FR light, PIFs predominantly inhibit starch synthesis. This study provides insight into the physiological and molecular functions of phyB and its downstream transcription factors HY5 and PIFs in starch synthesis regulation, shedding light on the regulatory mechanism by which plants synchronize dynamic light signals with metabolic cues to module starch synthesis.

FAR-RED ELONGATED HYPOCOTYL3 increases leaf longevity by delaying senescence in arabidopsis.

Senescence is the final stage of leaf development, limits and dictates the longevity of leaf. This stage is strictly controlled by internal developmental age signals and external environmental signals. However, the underlying mechanisms by which various signals integrating together to regulate leaf senescence remain largely unknown. Here, we show that the light signalling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) directly represses the transcription of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and NON-YELLOWING1/STAY-GREEN1 (NYE1/SGR1), two key regulators of senescence, thus preventing chlorophyll degradation and extending the leaf longevity in Arabidopsis thaliana. Disrupting either PIF4 or NYE1 function completely rescued the early leaf senescence of fhy3-4 mutant. Interestingly, we found that FHY3 competes with PIF4 to bind to the G-box cis-element in NYE1 promoter, subsequently preventing the transcriptional activation of this gene by PIF4. Moreover, FHY3 transcript levels gradually increased in senescent leaves, which consist with disrupting FHY3 function accelerated chlorophyll degradation and shorted the leaf longevity. All these findings reveal that FHY3 is a master regulator that participates in multiple signalling pathways to increase leaf longevity. In addition, our study shed light on the dynamic regulatory mechanisms by which plants integrate light signalling and internal developmental cues to control leaf senescence and longevity.

Site-specific crosslinking and assembly of tetrameric ß-glucuronidase improve glycyrrhizin hydrolysis.

In this study, eight nonconserved residues with exposed surfaces and flexible conformations of the homotetrameric PGUS (ß-glucuronidase from Aspergillus oryzae Li-3) were identified. Single-point mutation into cysteine enabled the thiol-maleimide reaction and site-specific protein assembly using a two-arm polyethylene glycol (PEG)-maleimide crosslinker (Mal2 ). The Mal2 (1k) (with 1 kDa PEG spacer)-crosslinked PGUS assemblies showed low crosslinking efficiency and unimproved thermostability except for G194C-Mal2 (1k). To improve the crosslinking efficiency, a lengthened crosslinker Mal2 (2k) (with 2 kDa PEG spacer) was used to produce PGUS assembly and a highly improved thermostability was achieved with a half-life of 47.2-169.2 min at 70°C, which is 1.04-3.74 times that of wild type PGUS. It is found that the thermostability of PGUS assembly was closely associated with the formation of inter-tetramer assembly and intratetramer crosslinking, rather than the PEGylation of the enzyme. Therefore, the four-arm PEG-maleimide crosslinker Mal4 (2k) (with 2 kDa PEG spacer) was employed to simultaneously increase the inter-tetramer assembly and intratetramer crosslinking, and the resulting PGUS assemblies showed further improved thermostabilities compared with Mal2 (2k)-crosslinked assemblies. Finally, the application of PGUS assemblies with significantly improved thermostability to the bioconversion of GL proved that the PGUS assembly is a strong catalyst for glycyrrhizin (GL) hydrolysis in industrial applications.

Salidroside alleviates diabetic neuropathic pain through regulation of the AMPK-NLRP3 inflammasome axis.

High glucose (HG)-induced nucleotide-binding and oligomerization (NACHT) domain, leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome activation leads to diabetic neuropathic pain. We recently showed that salidroside could suppress NLRP3 inflammasome activation in hepatocytes exposed to HG. The aim of this study was to evaluate the analgesic effect of salidroside on diabetic rats and to explore its underlying mechanisms. Rat models with diabetic neuropathic pain were induced by high-fat diet feeding combined with low dose streptozotocin injections. Doses of salidroside at 50 and 100 mg.kg-1.day-1 were administered by gavage to diabetic rats for 6 weeks. Mechanical allodynia test, thermal hyperalgesia test and biochemical analysis were performed to evaluate therapeutic effects. Primary dorsal root ganglion (DRG) cells exposed to HG at 45 mM were used to further study the effects of salidroside on the AMP-activated protein kinase (AMPK)-NLRP3 inflammasome axis and insulin sensitivity in vitro. Salidroside administration improved hyperglycemia, ameliorated insulin resistance, and alleviated neuropathic pain in diabetic rats. Moreover, salidroside induced AMPK activation and suppressed NLRP3 inflammasome activation in the DRGs of diabetic rats. In addition, salidroside treatment relieved oxidative stress, improved insulin sensitivity and regulated the AMPK-NLRP3 inflammasome axis in HG-treated DRGs in vitro. Furthermore, AMPK inhibition in vivo or AMPK silencing in vitro abolished the beneficial effects of salidroside on diabetic neuropathic pain. Together, these results indicate that salidroside alleviates diabetic neuropathic pain through its regulation of the AMPK-NLRP3 inflammasome axis in DRGs.

Improve the performance of full-scale continuous treatment of municipal wastewater by combining a numerical model and online sensors.

Mathematical models based on instant environmental inputs are increasingly applied to optimize the operation of wastewater treatment plants (WWTPs) for improving treatment efficiency. This study established a numerical model consisting of the activated sludge module ASM3 and EAWAG bio-P module, and calibrated the model using data from a full-scale experiment conducted in a WWTP in Nanjing, China. The calibrated model was combined with online sensors for water temperature, chemical oxygen demand, NH+ 4-N and PO3- 4-P to optimize and dynamically adjust the operation of the WWTP. The results showed that, compared to the original default operation mode, the effluent water quality was significantly improved after optimization even without supplementation of external carbon or alkalinity, and the required aeration rate in spring, summer, autumn, and winter was reduced by 15, 41, 33 and 11%, respectively. The study indicated that there was the potential for application of closed-loop automatic control to regulate operating parameters to improve wastewater treatment processes through the integration of data on influent characteristics and environmental conditions from sensors, and results from simulation models.

Optimizing external carbon source addition in domestics wastewater treatment based on online sensoring data and a numerical model.

The removal of total nitrogen in wastewater treatment plants (WWTPs) is often unsatisfactory for a variety of reasons. One possible measure to improve nitrogen removal is the addition of external carbon. However, the amount of carbon addition is directly related to WWTP operation costs, highlighting the importance of accurately determining the amount of external carbon required. The objective of this study was to obtain a low nitrate concentration in the anoxic zone of WWTPs efficiently and economically by optimizing the external carbon source dosage. Experiments were conducted using a pilot-scale pre-denitrification reactor at a Nanjing WWTP in China. External carbon source addition based on online monitoring of influent wastewater quality and a developed nitrification-denitrification numerical model was investigated. Results showed that carbon addition was reduced by 47.7% and aeration costs were reduced by 8.0% compared with those using a fixed-dose addition mode in the pilot reactor. The obtained technology was applied to the full-scale Jiangxinzhou WWTP in Nanjing with promising results.

Simultaneous denitrification and denitrifying phosphorus removal in a full-scale anoxic-oxic process without internal recycle treating low strength wastewater.

Performance of a full-scale anoxic-oxic activated sludge treatment plant (4.0×10(5) m(3)/day for the first-stage project) was followed during a year. The plant performed well for the removal of carbon, nitrogen and phosphorus in the process of treating domestic wastewater within a temperature range of 10.8°C to 30.5°C. Mass balance calculations indicated that COD utilization mainly occurred in the anoxic phase, accounting for 88.2% of total COD removal. Ammonia nitrogen removal occurred 13.71% in the anoxic zones and 78.77% in the aerobic zones. The contribution of anoxic zones to total nitrogen (TN) removal was 57.41%. Results indicated that nitrogen elimination in the oxic tanks was mainly contributed by simultaneous nitrification and denitrification (SND). The reduction of phosphorus mainly took place in the oxic zones, 61.46% of the total removal. Denitrifying phosphorus removal was achieved biologically by 11.29%. Practical experience proved that adaptability to gradually changing temperature of the microbial populations was important to maintain the plant overall stability. Sudden changes in temperature did not cause paralysis of the system just lower removal efficiency, which could be explained by functional redundancy of microorganisms that may compensate the adverse effects of temperature changes to a certain degree. Anoxic-oxic process without internal recycling has great potential to treat low strength wastewater (i.e., TN<35 mg/L) as well as reducing operation costs.

Uncertainty analyses on the calculation of water environmental capacity by an innovative holistic method and its application to the Dongjiang River.

The estimation and allocation of water environmental capacity (WEC) are essential to water quality management and social-economic interests. However, there is inevitable uncertainty in the capacity estimation due to model conceptualization, data collection and parameter calibration. An innovative holistic approach was developed, which took both independence and relevance between parameters into account to analyze the uncertainties in WEC calculation and estimate the margin of safety. The Dongjiang River was taken as the case to demonstrate the method, focusing on the chemical oxygen demand and NH4(+)-N that were the two major water quality problems in the river. The results showed that the proposed holistic approach is very promising and applicable compared to traditional methods of uncertainty analysis.

Clinical application of medical adhesive in endovascular embolization treatment of peripheral pseudoaneurysm.

Objectives: This study explores the clinical application value of medical adhesive in endovascular embolization treatment of peripheral pseudoaneurysm. Material and Methods: This was a retrospective review on 31 patients with peripheral pseudoaneurysm treated with medical adhesive endovascular embolization at the First Affiliated Hospital of Shihezi University from July 2021 to July 2023. Follow-up for 3-6 months was to observe the clinical efficacy and postoperative complications of medical adhesive embolization treatment. Results: A total of 32 pseudoaneurysms were embolized in 31 patients with peripheral pseudoaneurysms. All pseudoaneurysms originated from visceral arteries. Among them, 29 pseudoaneurysms were embolized with medical adhesive alone, and three pseudoaneurysms were embolized with coil-assisted medical adhesive. After endovascular embolization with medical adhesive, all pseudoaneurysms were successfully embolized. Technical success was 100%. All patients experienced cessation of bleeding after endovascular embolization with medical adhesive, and there were no serious post-operative complications. Clinical success was 100%. During the follow-up period, two patients experienced recurrent bleeding but no pseudoaneurysm recurrence was observed. Conclusion: Endovascular medical adhesive embolization is a safe and effective method for treating pseudoaneurysm, with high hemostatic efficiency and permanent occlusion of the pseudoaneurysm after embolization, which is worthy of clinical promotion and application.

The tRF-3024b hijacks miR-192-5p to increase BCL-2-mediated resistance to cytotoxic T lymphocytes in Esophageal Squamous Cell Carcinoma.

The limited efficacy of immune checkpoint inhibitors (ICIs) in the treatment of advanced Esophageal Squamous Cell Carcinoma (ESCC) poses a challenge. Recent evidence suggests that tumor cells' insensitivity to cytotoxic T lymphocytes (CTLs) contributes to drug resistance against ICIs. Here, a particular tRNA-derived fragment called tRF-3024b has been identified as playing a significant role in tumor cell resistance to CTLs. Through tRF sequencing (tRF-seq), we observed a high expression of tRF-3024b in ESCC cells that survived co-culture with CTLs. Further in vitro studies demonstrated that tRF-3024b reduced the apoptosis of tumor cells when co-cultured with CTLs. The mechanism behind this resistance involves tRF-3024b promoting the expression of B-cell lymphoma-2 (BCL-2) by sequestering miR-192-5p, a microRNA that would normally inhibit BCL-2 expression. This means that tRF-3024b indirectly enhances the protective effects of BCL-2, reducing apoptosis in tumor cells. Rescue assays confirmed that the suppressive function of tRF-3024b relies on BCL-2. In summary, the tRF-3024b/miR-192-5p/BCL-2 axis sheds light on the crucial role of tRF-3024b in regulating BCL-2 expression. These findings offer valuable insights into strategies to enhance the response of ESCC to CTLs and improve the effectiveness of immunotherapy approaches in treating ESCC.

The combination of nanotechnology and potassium: applications in agriculture.

Potassium fertilizer is indispensable for ensuring crop production, which in turn supports global food supply and safe farming practices. Potassium resources are primarily located in the Northern Hemisphere, leading to a current shortage of affordable potash and severe soil deficiencies in certain regions of the Southern Hemisphere. There is a shift away from mined salts in favor of locally available potassium resources. Utilizing potassium-rich silicates, for instance, could be a viable option to address this situation. The imperative of enhancing crop productivity and quality necessitates either increasing potassium availability or utilizing potassium more efficiently. Geneticists may find the development of plants that use potassium more effectively to be a valuable pursuit. Nanomaterials are increasingly becoming part of people's professional lives as a novel material category. This technology is gradually finding applications in agriculture to boost crop yields while reducing environmental pollution. This paper reviews the applications of common potassium-containing materials, explores the effects and mechanisms of nano-fertilizers on plants, and offers insights into future applications of nano-potassium fertilizers in agriculture. All in all, the application of nanotechnology in the production and utilization of potassium fertilizers is both necessary and effective. However, there are still many gaps in the current field of nano-potassium fertilizer application that require further research. It is hoped that this review can serve as a valuable reference for researchers working in this field.

Investigation of the effects and mechanisms of manganese-based NMs on rice growth.

Manganese-based (Mn-based) nanomaterials (NMs) have great potential as alternatives to conventional Mn fertilizers. Yet, its environmental risks and effects on plant growth are not completely well understood. This study investigated the physiological effects of manganese dioxide (MnO2) and manganese tetroxide (Mn3O4) NMs on inter-root exposure (0-500 mg/L) of hydroponically grown rice. The results showed that on inter-root exposure, 50 mg/L Mn-based NMs promoted the uptake of mineral elements and enhanced the enzymatic activities of antioxidant systems (CAT and SOD) in rice, whereas 500 mg/L Mn3O4 NMs disrupted the mineral element homeostasis and led to phytotoxicity. The promotion effect of MnO2 NMs was better, firstly because MnO2 NMs treatment had lower Mn content in the plant than Mn3O4 NMs. In addition, MnO2 NMs are more transported and absorbed in the plant in ionic form, while Mn3O4 NMs exist in granular form. MnO2 NMs and Mn3O4 NMs both can be used as nano-fertilizers to improve the growth of rice by inter-root application, but the doses should be carefully selected.

Preparation of ethyl cellulose bimodal nanofibrous membrane by green electrospinning based on molecular weight regulation for high-performance air filtration.

Preparing bio-based air filtration membrane through green electrospinning strategy is a vital approach to alleviating environmental and energy crises. However, the development of related biomaterials and method for regulating membrane structure are still lacking. In this study, ethyl cellulose (EC) bimodal nanofibrous membrane was prepared by electrospinning using ethanol and water as solvents to achieve high-performance air filtration. A new strategy for bimodal fiber molding based on molecular weight modulation was proposed. The EC polymer chains with medium molecular weights were subject to the highest degree of inhomogeneity of solvent intrusion, and there were significant differences in viscous forces "microscopically", leading to the formation of bimodal structure by inhomogeneous stretching of the jet. The well-defined bimodal structure endowed EC membrane with excellent air filtration performance. The filtration efficiency for PM0.3, pressure drop, quality factor were 99.11 %, 42.2 Pa, and 0.112 Pa-1, respectively. Compared to the commonly used zein, EC cost just 12.77 %, and its solution had a 50 % longer shelf life, making it a more desirable biomaterial. This work will facilitate the application of more biomaterials in air filtration, promote the green fabrication of high-performance air filtration membranes, and realize sustainable development.

Unlocking the potential of nanoscale sulfur in sustainable agriculture.

The global population is growing rapidly, which poses a significant challenge to food security. Innovation in agricultural technologies is necessary to achieve sustainable development in agriculture and combat food insecurity. Nanotechnology has emerged as a promising tool in agriculture; compared to conventional agricultural chemicals, demonstrated benefits include increased efficiency of delivery and utilization of both nutrients and pesticides, as well as nanoscale-specific stimulation of stress tolerance pathways. Among the many studied nanomaterials, nano-sulfur has demonstrated superior effects at enhancing plant resilience to pathogens and abiotic stresses, as well as improving plant growth and nutritional quality of edible tissues. A number of published studies have investigated the physiological effects (growth promotion, disease resistance) of single or several sulfur and sulfide compounds on crop species. However, there is no systematic analysis of this literature, including the effects and specific mechanisms of various sulfur forms in agricultural applications. In this review, we will discuss the effects of sulfur (including nano-sulfur) on crop species, the underlying mechanisms of action for their transport and transformation in the soil-plant system, and evaluate their suitability in sustainable agricultural development. Additionally, we discuss the current challenges and knowledge gaps for nanoscale sulfur use in agriculture, and describe future research directions to advance our understanding of the sustainable use of this material at the scale of individual fields.

Histological and single-nucleus transcriptome analyses reveal the specialized functions of ligular sclerenchyma cells and key regulators of leaf angle in maize.

Leaf angle (LA) is a crucial factor that affects planting density and yield in maize. However, the regulatory mechanisms underlying LA formation remain largely unknown. In this study, we performed a comparative histological analysis of the ligular region across various maize inbred lines and revealed that LA is significantly influenced by a two-step regulatory process involving initial cell elongation followed by subsequent lignification in the ligular adaxial sclerenchyma cells (SCs). Subsequently, we performed both bulk and single-nucleus RNA sequencing, generated a comprehensive transcriptomic atlas of the ligular region, and identified numerous genes enriched in the hypodermal cells that may influence their specialization into SCs. Furthermore, we functionally characterized two genes encoding atypical basic-helix-loop-helix (bHLH) transcription factors, bHLH30 and its homolog bHLH155, which are highly expressed in the elongated adaxial cells. Genetic analyses revealed that bHLH30 and bHLH155 positively regulate LA expansion, and molecular experiments demonstrated their ability to activate the transcription of genes involved in cell elongation and lignification of SCs. These findings highlight the specialized functions of ligular adaxial SCs in LA regulation by restricting further extension of ligular cells and enhancing mechanical strength. The transcriptomic atlas of the ligular region at single-nucleus resolution not only deepens our understanding of LA regulation but also enables identification of numerous potential targets for optimizing plant architecture in modern maize breeding.

Phytochrome B interacts with LIGULELESS1 to control plant architecture and density tolerance in maize.

Over the past few decades, significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant. However, dense planting triggers shade avoidance responses (SARs) that optimize light absorption but impair plant vigor and performance, limiting yield improvement through increasing plant density. In this study, we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B (phyB1/B2), the primary photoreceptor responsible for perceiving red (R) and far-red (FR) light in maize. We found that maize phyB physically interacts with the LIGULELESS1 (LG1), a classical key regulator of leaf angle, to coordinately regulate plant architecture and density tolerance. The abundance of LG1 is significantly increased by phyB under high R:FR light (low density) but rapidly decreases under low R:FR light (high density), correlating with variations in leaf angle and plant height under various densities. In addition, we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade. Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells. Taken together, these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance, providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.

Phosphorus-based nanomaterials as a potential phosphate fertilizer for sustainable agricultural development.

Phosphorus-based nanomaterials (PNMs) have been reported to have substantial promise for promoting plant growth, improving plant tolerance mechanisms, and increasing resistance to pathogenic organisms. Recent scientific investigation has demonstrated that utilizing PNMs can enhance plant physiological growth, photosynthetic pigments, antioxidant system, metabolism, nutrient absorption, rhizosphere secretion, and soil nutrients activation. Previous research on PNMs mostly concentrated on calcium phosphate, zeolite, and chitosan, with little systematic summarization, demanding a thorough evaluation of PNMs' broader uses. In our current review article, we address the knowledge gap by classifying PNMs according to green synthesis methods and the valence state of phosphorus while elucidating the underlying mechanisms through which these PNMs facilitate plant growth. In addition, we also targeted some strategies to improve the bioavailability of PNMs, offering valuable insights for the future design and safe implementation of PNMs in agricultural practices.

Salidroside protects pancreatic ß-cells against pyroptosis by regulating the NLRP3/GSDMD pathway in diabetic conditions.

The NACHT, LRP, and PYD domains-containing protein 3 (NLRP3) inflammasome-evoked chronic inflammation is involved in the pathogenesis of diabetes mellitus (DM), and the NLRP3/gasdermin D (GSDMD)-mediated canonical pathway of pyroptosis leads to the loss of pancreatic ß-cells and failure of pancreatic function in DM. A previous study demonstrated that salidroside (SAL) alleviates the pathological hyperplasia of pancreatic ß-cells in db/db mice. However, it is not clear whether the NLRP3/GSDMD pathway-mediated pyroptosis can be regulated by SAL. In addition, the action of SAL on pancreatic ß-cells in DM remains poorly understood. Thus, this study aimed to investigate the effects and underlying mechanisms of SAL on pancreatic ß-cell pyroptosis. Rat insulinoma (INS-1) cells were cultured in a medium containing either high glucose (HG) or HG plus high insulin (HG-HI), and the effects of SAL on cell viability, AMP-activated protein kinase (AMPK) activity, reactive oxygen species (ROS) generation, NLRP3/GSDMD activation, and pyroptotic body formation were assessed. Streptozocin-induced DM mice were used to further investigate the effects of SAL on pancreatic pyroptosis. The results revealed aberrances on cell viability, AMPK activity, ROS generation, NLRP3/GSDMD activation, and pyroptotic body formation in HG- and HG-HI-exposed INS-1 cells; these abnormal effects were corrected by SAL in both a concentration- and AMPK-dependent manner. Moreover, SAL administration activated AMPK, suppressed NLRP3/GSDMD signaling, and protected pancreatic ß-cells against pyroptosis in DM mice. These findings suggest that SAL promotes AMPK activation to suppress NLRP3/GSDMD-related pyroptosis in pancreatic ß-cells under DM conditions.

Tetramerization of GH2 ß-Glucuronidases is Essential for Catalyzing the Hydrolysis of the Large Substrate Glycyrrhizin.

In this study, structural analysis was employed to identify three hotspot residues that contribute most to the tetramer formation of a glycoside hydrolase family 2 (GH2) ß-glucuronidase (GUS) from Aspergillus oryzae Li-3. Single-point mutation at these sites completely disrupted the tetramer structure and abolished the glycyrrhizin (GL)-hydrolyzing activity. Then, the W522A dimer was refactored into a tetramer by disulfide bonding, and partial GL activity was restored. Further saturated mutation showed a strong correlation between the GL activity of the mutants and their tetramer ratios. Molecular simulations were employed to illustrate the critical role of the tetramer interface in maintaining a functional active-site structure. The three highly conserved tetramer-forming residues were finally applied to two other GH2 GUSs for tetramer dissociation and demonstrated the significance of the homotetramerization for GL-hydrolyzing activity of GH2 GUSs. This study lays foundation for engineering GL-hydrolyzing GUSs at the quaternary structure level for function regulations.